Pneumatic body and fender hammer



April 11, 1944. BQRM PNEUMATIC BODY AND FENDER HAMMERS 2 Sheets- Sheet 1 Filed Jan. 12. 1942 INVENTOR. Frdz'narzd' .Borm

W Y HIS .ATTORN BY WITNESSES F. H. BORM PNEUMATIQ BODY AND FElfDER HAMMERS April 11, 1944.

2 Sheets-Sheet 2 Filed Jan. 12, 1942 INVENTOR km" ATTORNEY I Fer z'rzarzdIiB Patented Apr. 11, 1944 UNITED STATES PATENT OFFICE 2,346,532 PNEUMATIC BODY AND FENDER HAMMER Ferdinand a. 5m, Elgin, 111. Application January 12, 1942, Serial No. 426,463 Claims. (01. 153-48) This invention relates to power tools, such as body and fender hammers, and the like, and the primary object thereof is to provide novel and simple means for bringing the motor body or hammer head against the die and interposed work or sheet of metal under desired tension which may be adjusted or increased as the work progresses, without removing the tool from the work so as to facilitate gradual flattening or straightening thereof, and to provide simple means for positively holding the parts locked against accidental loosening from vibration at any particular adjustment, while permitting easy release thereof.

Another object of the invention is to provide a power tool or body and fender hammer especially of the pneumatic or air type in which the hammer head or motor body is slidably mounted on the frame, especially by means of an upright post on the frame and an extension sleeve on the hammer head adapted to be held or clamped under desired pressure toward a confronting die and the work on a corresponding portion of the frame to tension the device and frame and adjust or cause the hammer head to be held against the work at the desired pressure which is increased as the straightening operation proceeds, so as to facilitate the straightening or flattening of dented fenders, bodies or turret tops or other parts of different shapes to be repaired so that dented or crumpled fenders, automobile body portions, and similar parts which have been damaged, can be effectively smoothed or ironed out.

Another object of the invention is to not only mount the motor body or hammer head for limited free sliding movement relative to the die and frame, but also to permit adjustment of the pressure against the die and work such as dented or crumpled fenders and the like during the straightening operation and without removing the hammer head from its mounted position on the frame, but also to permit quick and convenient removal of the hammer head to. facilitate application of the device to and removal from various parts, including deep skirted fenders without the necessity of removing the wheels of an automobile, bodies and turret tops, irrespective of their formation and to make it possible for the operator to work the hammer in all directions and to get at usually inaccessible places and permitting hammering out of the damaged metal in a fraction of the time, or less time, than usually required for such operations vice so that less parts are required and eliminating or reducing the necessity of replacing'worn parts.

Another object of the invention is to provide a hammer in which the head and frame are slidably connected or free to slide on one another so that the head will normally drop down into engagement with the die and work when the frame is supported, or the frame may drop down relative to the head to separate the head and die or work when the head is supported, the head being mounted to freely slide on an upright post of a frame, preferably of a resilient type having confronting portions, the head bein mounted on the upper supporting portion or arm of the frame or yoke, and the die being supported on the lower arm or supporting portion, while simple means is provided in the form of a nut threaded on the post to engage the head or a sleeve extension thereof to adjust the tension of the frame and of the head against the' work, said nut having means to positively lock it in adjusted position, while the structure permits quick separation of the head and die a sumcient distance to render it possible 7 to more quickly apply or remove the hammer to and from the work, while the tension may be adjusted while the tool is in operation.

Another object of the invention is to provide simple and novel'means for adjusting the tension of the device or frame and the pressure of the head against the die and work by mounting the head for free sliding movement on the frame, preferably on the upper portion thereof to be quickly set or brought against the work initially or adjusted as to tension or force against the i die and work with a resilient bowed or yoke frame having an upright post thereon on which a rigid sleeve extension of the hammer head or body is vertically slidable and held against turnmg, aS well as adapted to be held down at any desired tension, and positively locked against getting loose when once set.

Another object of the invention is to permit minute adjustment of the tension with ease and without turning or altering the position of the head or body relative to the frame or die and work, or permitting disalignment of the head and its striker and the die as with devices where it is necessary to shift or turn the head to secure adjustment and which require the air hose to be swiveled at the top or to project above the axis of the head'where it is in the way and interferes with the operation of the hammer.

. Another object of the invention is to permit the use of interchangeable supporting frames for various operations and to simplify tools of this character and save time and labor, as'well as to facilitate straightening or flattening of metal, particularly dented or damaged parts of automobiles.

Another object of the invention is to provide a power tool, especially an air or pneumatic body and fender hammer with a cushion blow and requiring less manual efiort for operation by means of a simple and novel tension adjustment which can be easily controlled or adjusted while the hammer is in operation and conveniently located to allow the operator to secure the desired tension for the Another object of the invention is to provide a tool of the class described, including a holding frame having confronting portions and novel means of mounting a motor body or hammer head with a striker on one portion of the frame for free sliding movement in opposition to a die on the other portion of the frame, and means for exerting pressure on the motor body or harm: mer head to adjust the tension of the device particular work to be done.

v a nut on the post and frame, and of the motor body or hammer head against the die and interposed work to most effectively straighten, hammer out, and smooth the metal when deflected or dented, and which will permit a relatively inexperienced person to operate the same without damaging the metal or requiring heating and shrinking thereof.

Another object of the invention is to permit the application of the hammer to and release or removal from the work by simply operating the tension control or releasing the tension to permit the motor body or head to freely slide toward or away from the die to decrease or increase the space therebetween; to permit easy control of the volume and supply of air or other fluid, as by means of a depressible operating lever equipped with a knurled screw for adjusting and setting the power control, volumeof air or degree of opening of the valve and'maintaining or keeping the same open, as desired.

Another object of the invention is to so mount the hammer head on the frame that the hammer head or motor body forms a convenient handle to grasp and hold the tool at the point of greatest heft to greatly facilitate movement and accurate guiding thereof over the work without quickly tiring the operator and to obviate the usual necessity for a tight gripping and awkwardness in the handling of the tool, and, in addition, to permit the same to be operated with either hand, which is also used to operate a lever for controlling a valve supplying compressed air or fluid for operating the hammer striker or impact member.

Another object of the invention is to provide a body and fender hammer with means to mount a hammer head on the supporting or holding frame, particularly the upper portion of a resilient bowed frame of high grade steel tubing or malleable iron pipe to give resiliency thereto while the hammer head is adapted for free sliding movement to facilitate application of the tool to the work and removal therefrom while held against turning and normally spaced from said frame portion when the hammer head is engaged with a die on the lower portion of the frame and means to adjust the tension of the device or frame to secure the desired pressure,

stroke and force of impact exerted against the work conflned between the hammer striker and die on impact whereby to quickly and efliciently iron out rough spots in the metal being straightened.

Still another object is to provide me ns t positively hold the hammer against the die and work under desired tension or at any adjusted position and to readily release the same.

Another object of the invention is to provide a tool of the class described in which the hammer head or motor body is removably mounted to facilitate application of the tool to the work when necessar and also mounted for free sliding movement on a confronting portion of the frame while held against turning in perfect alignment with the die on the other confronting portion of the frame, but normally spaced fiom the frame part on which it is mounted when engaged with the die or interposed work, usually themetal sheet being flattened and adapted to be slidably pressed toward the work at any desired pressure by means acting on the head or a sleeve extension thereof by which it is slidably mounted on a post of the frame, as by turning whereby turning and possible disalignment of the head with respect to the die is obviated, and whereby the device may be tensioned and the apron of the head held against or caused to hug the work on the die in the die holder and adjusted to increase the tension as the operation progresses to gradually remove bumps or bends and prevent it from chattering or jumping out of position.

Another object of the invention is to securely lock or hold the head at an adjusted tension as by means of a simple spring catch on the nut to engage seats or depressions in the extension sleeve of the head, the head forming a handle permitting the device to be gripped near the top of the frame, thereby rendering the device easy to manipulate and obviating tight gripping to secure the necessary pressure on the work which is usually required with tools of this character, and results in the hands becoming numb from the tight gripping and vibration.

Further objects and advantages will appear and be brought out more fully in the following specification, reference being had to the accompanying drawings, in which:

Fig. 1 is a side elevation of a hammer partly broken away and in section and constructed in accordance with the invention, with the hammer head and connected sleeve member attached to one type of holding frame in operative position and upon which the die holder is mounted on the opposite side of the work from the hammer head;

Fig. 2 is a top plan view of the device as shown in Fig. 1 with the clamping or look nut for adjusting the hammer head in dotted lines and the air supply conduit in position;

Fig. 3 is a fragmentary vertical section taken on the line 3-3 of Fig. 1;

Fig. 4 is an enlarged vertical sectional view taken on the line 4-4 of Fig. 2 of the hammer head and die holder;

Fig. 5 is a horizontal sectional view taken on the line 55 of Fig. 4;

Fig. 6 is a sectional elevation taken on the line 6-6 of Fig. 4;

Fig. 7 is a rear elevation of the motor body or hammer head removed from the frame; and

Fig. 8 is a detailed elevation of a holding spring or pawl for the volume control.

Referring more particularly to the drawings,

assassa I. designates a supporting or holding frame of any desired character, but preferably formed of resilient tubing usually of high grade steel tubing or spring malleable iron pipe usually of the bowed type in the form of a yoke adapted to straddle a fender, body part or other section of sheet metal for working engagement or operation, usually a dented or crumpled automobile fender, body portion or turret top to be ironed out, flattened or straightened. Special shapes of frames or arms for supporting the tool may be provided and interchangeably fitted to accommodate deep skirted fenders, for body work or turret tops where an extremely long sweep is required, but the frame shown is symbolic by way of example and substantially oval or circular in outline. The lower extremity, arm or supporting portion ll of the frame member i is curved upwardly and forwardly to support a lower die member or socket I! which is preferably in the form of a casting or sleeve, dolly or die formed of obtuse angled formation having sockets at opposite ends thereof,

and which is preferably aflixed rigidly to the end portion Ii, but adapted to be released and sub stituted by any other form of die holder. The frame member extends within a bore II in the lower portion of the hie holder which is in the form of a sleeve having a transverse intermediate portion or end wall engaged by the upper end of the lower supporting portion or arm ll of the frame and a split or slotted portion or sleeve l4 at the lower portion or hub thereof and provided with clamping ears l5 connected by a locking pin or clamping bolt I 6 by which the die holder may be held in adjusted position against angular turning on the portion ll of the frame or released and adjusted, if desired. The upper portion ll of the die holder or sleeve composing the same above the intermediate portion may be provided with a circular or other form of socket H to removably receive a similarly shaped shank take a vertical post 34 which may be fixed thereto by a pin or dowel 85 or otherwise rigidly secured in position as by sweating, chilling, pinning, keying or otherwise rigidly secured against turning.

This post has a threaded upper portion 38 for a greater portion of the length thereof, but is flattened at the back as indicated at 31 and the threaded portion is adapted to take a clamping head or lock nut 38, preferably winged as shown, to facilitate turning and tightening thereof. The top portion of the post is preferably unthreaded as at 34a to facilitate application of the nut. This nut, in connection with the hammer head or motor body, and more particularly a rigid sleeve extension thereof with which the nut cooperates, constitutes means to tension the device and adjust said tension or resiliency, particularly of the frame and of the hammer head against the work and die as the work progresses without removing the motor body or hammer head from the frame, as will be fully described. The hammer head 26 has an upper vertical and lateral inward extension 39 at the top in the form of a web or block preferably formed integrally with the hammer head or motor body and forming part of a sleeve extension terminating at its inner end in a vertical solid or rigid sleeve or post IQ of a die 20, of the dolly or anvil of which any number may be provided, including a centering or line-up die. All of these dies are made of hardened steel and capable of being quickly changed and are of various contours for application in relation to the work to be done.

' In the form shown,a shoulder 2| engages the top of the upper portion i'l around the socket or sleeve l8 and has a flange 22 slightly below the reduced top portion 23 thereof and which may have a central circular indentation 24. The reduced top portion is designed to fit within the apron or skirt 25 of the motor'body or hammer head 26 so as to accurately align the motor body or head and striker 21 thereof in operative position.

The upper horizontal portion or arm 28 of the frame extends substantially in confronting relation to the lower portion II but slightly rearwardly oflset therefrom and spaced above the same and receives a removable split sleeve or clamp 29 which is rigidly mounted on or afllxed ithereto through the medium of the bore of the the sleeve may be firmly held against turning on the frame, but readily removed when desired for application to frames of other shapes according to the work at hand. The free end of the sleeve 29 preferably has a flattened circular extension 33 with a flat top face and bored vertically to 40 having a smooth bore adapted to freely slide vertically over the upright post 36 including the threaded portion thereof. A segmental spline plate or key 4| is secured in the bore of the sleeve 40 at the inside or back as by means of screws 42 engaged through openings 43 in the sleeve with countersinks at the-flattened back portion of the sleeve to receive the heads of the screws flush and threaded openings 44 in the key or plate II to securely fasten the latter in position and by engaging the flattened face 31 extending as the cord of an arc of the post to positively prevent the hammer head from turning horizontally on the post as a vertical axis. Normally, when the apron 25 of the hammer head is engaged with the die or work 45a usually of sheet metal such as a dented fender, body or turret top of an automobile, the bottom of the sleeve 40 is spaced from the flattened top face of the flattened extension 33 of the split sleeve 29 so as to place the device and the resilient frame under tension which may be adjusted by turning the nut 38 on the threads 36 against the top end of the sleeve 40. This may be conveniently and easily done by hand while the device is in use, and without the necessity of removing the hammer head from the frame so that the tension and pressure of the frame and of the hammer head against the work may be effectively adjusted, that is, increased or decreased, as desired, while the device is in operation. Also, by removing the nut or raising it, the space between the head and the die may-be enlarged, especially when the head is removed from the post and frame to greatly facilitate the application of the tool to places hard to get at or formations of metal which are usually difficult to apply the tool to, and to obtain access to usually inaccessible parts.

By omitting the spline plate or key 4|, with or without the flattened portion 31, the head 26 and sleeve 40 maybe readily turned horizontally on the post 34 as a vertical axis to any desired lateral or angular position and lined up with the die by correspondingly adjusting the die holder or anvil l2 on the lower arm H. This is due to the fact that the die holder is of obtuse angled formation with the upper portion l1 and socket il extending vertically.

This operation is also In order to eifectively lock and hold the hammer head downwardly under pressure to tension the device or frame and the engagement of the hammer head with the die, the nut 38 is turned on the threads 36 of the post 84 against the top edge or end 45 of the sleeve 46, and means is provided to hold the nut against rotation in different positions. As shown, this consists in pro viding the upper end 45 with a series of indentations 46 preferably located ninety degrees apart and four in number, or otherwise suitably positioned to take a tapered pin, pawl or spring pressed detent 41 inserted in a bottom counterbore 48 in the 'nut parallel to the axis thereof and receiving a spring 49 which presses downwardly on the pin between the end of the counterbore and the top of the pin. To prevent displacement of the pin, the metal around the open "end of the counterbore or socket 48 is upset or confined as indicated at 50. Thus, this pin will snap into the depressions 46 as the nut is turned, and positively hold the nut against turning in either direction and pressed firmly against the top of the sleeve 46 so as to force the latter downwardly on the post 34 permitted by the spacing of the lower end of the sleeve from the flattened top face of the sleeve extension 33 with the hammer head in engagement with the die to increase or decrease the tension of the device and frame and force exerted against the work. This tension may be increased as the work of smoothing out the metal progresses, and may be accomplished by turning the nut 38 while the device is in operation without the necessity of turning the head relative to the frame or its axis and normally maintain the head in alignment with the die and the plane of the frame so that possible disalignment of the hammer head and die is prevented. It also eliminates the necessity of mounting the head for turning movement or providing a threaded connection thereof with the frame or sleeve 29 mounted thereon. As the pressure is increased between the nut 38 and the head at the top of the sleeve 40, the latter is forced down-' wardly on the post to shorten the space between the lower end of the sleeve and the sleeve extension 33 whereby to place the whole frame or yoke under increased tension to hold the apron of the hammer head against the work and prevent the same from chattering or jumping out of position.

extension 40 of the motor body or hammer head. On the other hand, the release of the pressure and tension may be readily accomplished by unscrewing the nut 38, the pin 41 snapping into and out of the depressions 46 so as to readily separate the head and die and permit the head to rise on the post 34 until this tension or pressure is relieved. However, by removing the nut 38, the hammer head may be entirely displaced from the frame or supporting post thereof for convenience in applying the device to, or removing it from By increasing this tension and the pressure as s the smoothing operation progresses, the completion of the work is greatly facilitated so as to require less time and insure a much smoother product without possible damage to the metal. greatly facilitated due to the fact that the head the tool is guided over the work with either hand in line with the top of the frame and vertically in alignment with the hammer head and die where the force of impact of the blows of the hammer striker or impact member are delivered and without tiring effect or the necessity of applying manual pressure or tightly gripping the hammer in order to produce the necessary pressure upon the work to effect the straightening thereof. The adjusting of the tension or pressure may be minutely regulatedand will act to spring the lower portion of the frame downwardly, which will result in a rebound thereof after each impact so that the striker and the die will closely hug the sheet of metal at all times, but the upward movement will be limited by the engagement of the nut 38 with the top of the sleeve is used as a handle and the work, if desired, although this is not usually necessary, or for replacement, repair or other purpose.

The hammer mechanism, per se, may be of conventional type, but as shown, the upper portion or the hammer head is provided with an enlarged central chamber or bore 5| and a reduced lower or central bore 62 forming the hammer cylinder with an enlarged flared or apron portion 53 open at the bottom and communicating with an enlarged bore 54 in the apron forming a socket which opens into a, vertical slot 55 at the inside of the hammer and terminating spaced from the bottom edge thereof to constitute an exhaust for fluid pressure or exhaust air. The piston is designated at 56 and is positioned to reciprocate within the bore 52 and has the striker head or impact member 21 mounted on its lower end, being provided with a top socket 51 for this purpose and secured by a radial pin or set screw 58 threaded through a, bore 59 radially of the striker head or through the wall thereof to engage at its reduced inner end 60 with a corresponding socket in the piston. The set screw or pin 58 preferably has a socket 6| for a hex-wrench to tighten or release the set screw so that the striker head may be removed or replaced, if desired, or found necessary. The striker head as thus mounted on the shank portion or lower end of the piston, which extends through the enlarged bore 54 forming an annular chamber around the piston at its lower portion, provides escape means for the fluid or air under pressure which is relieved through the vertical slot 55. The upper portion of the piston 56 is enlarged as at 62 to operate in the enlarged upper bore portion or chamber 5| of the motor body or hammer head, and the piston has an axial or central bore 63 of reduced diameter extending through the top into the enlarged chamber or bore 5| and down to a point spaced from the lower end of the shank or piston. The reduced lower portion of the piston 56 has diametrically aligned radial inlet ports 64 extending therethrough a short distance below the enlarged portion 62 and spaced below the same to admit air or other compressed fluid into the bore 63 and thus through said bore to the enlarged chamber 5| above the upper end of the piston. The piston is also provided at its juncture with the shank or lower portion thereof, bore 54 and slot 55 when the piston is down, with similarly related exhaust ports 65 which communicate with the bore 63 spaced above its lower end and also with the annular chamber or enlarged bore 54 at the lower portion of the hammer head. The

. upper portion of the bore 5| is internally threadduced bore portion 52, an annular chamber 89 is produced fora purpose to be subsequently I described.

of the radial arm or web forming the extension 39 extending substantially tangentially to the bore of the cylinder and forming a thickened wall at the back of the cylinder forming the upper portion of the motor body or hammer head, as more particularly shown in Fig.5 of the drawings. Of course, any desired form of fitting or coupling may be employed for connecting the hose to the hammer head. A transverse bore 13 is provided through this thickened wall perpendicular to the threaded connection of the hose and the outer end thereof is closed by a flanged plug 14 threaded into the bore with an interposedpacking or washer 15 and having a wrench head for facility in applying and removing the same. The inner end of the plug 14 is counterbored as shown at 16 to provide a retaining seat for the outer end of a coiled compression spring 11 in the bore or chamber 13 and this bore has a reduced portion 18 forming a valve seat 19 with a reduced stem 80 therethrough communicating with a chamber II for controlling the supply and volume of compressed fluid or air admitted to the cylinder for the purpose of regulating the force of impact and 7 speed of operation of the hammer, depending upon the pressure of the fluid or air, especially through the axial opening or port 18. The passage 18 is slightly larger than a valve stem 8| which extends therethrough and one end of the stem is threaded as at 82 to take an enlarged valve head 83 which is pressed against a shoulder or swell 84 on the stem with an interposed rubber or like gasket 85 to insure closing of the passage. A lock nut 88 is also threaded on the nut of the stem and has a notched flange 81 for receiving the opposite end of the spring 11 which thereby serves to normally seat the valve. The opposite end of the stem may be enlarged as indicated at 88 which passes through an axial bore 89 of a packing gland nut or ring 90 in the form of a plug threaded at 9| into a corresponding thread ed portion of a counterbore forming the supply chamber 8|. The stem preferably has a tapered end 92 projecting from the gland or nut 90 and constitutes means whereby the valve may be unseated in connection with an operating lever or flngerpiece 93, to be more fully described. This valve constitutes both an operating valve and a control valve for the volume of compressed air or other fluid admitted to the chamber and thus to the cylinder of the hammer mechanism, and as constituted, is held normally seated to cut off the supply of said fluid and prevent the escape of the compressed air or other fluid therethrough. The gland or nut 90 is also accommodated with the projecting end of the valve stem in a counterbore 94 in the adjacent side of the hammer head at the web portion 39 thereof near the bottom anda vertical groove 95 in the side of the hammer head adjacent the web portion intersects and extends upwardly from the counterbore 94 to form a seat and guideway for the operating lever orflnger: piece 93 which is thus protected against injury by the side walls or ribs at the sides of the It groove. This lever 93 is pivoted at 98 in the lower portion of the groove by means of a screw pin preferably threaded in a corresponding bore in the casting and inserted from the back or inside as indicated more particularly in Fig. 5 of the drawings so that the inner face of the lever will engage the adjacent end of the valve stem as seen especially in Fig. 3 of the drawings. A bowed spring 91 is fastened by two screws or otherwise anchored as indicated at 98 near the lower end or through the lever 93 and its' upper or free end portion is curved inwardly and provided with a central projection, punch or rib 99 on its inner face. An adjusting or lateral control screw I00 is threaded in a transverse bore or socket |0I in the wall of the hammer head at the web 39 thereof 'near the top and an enlarged knurled head I02 is provided on the screw, being preferably threaded, tight or flxed thereon and accommodated in a counterbore I03 communicating with the groove 95 at its upper end adjacent the top of the hammer head and at its web portion so.

that the knurled head I02 projects slightly above the top of the hammer head and web to permit convenient turning thereof. The outer face of the head has a plurality of radial notches I04 which are individually engaged by the rib 99 of the spring 91 so that the springs 11 and 91 not only serve to hold the lever 93 outwardly away from the valve stem so that the valve head 83 is normally seated to cut on the flow of compressed air, but the spring 91 also serves to hold the ad.- justing screwvl00 in adjusted position to limit the degree of depression movement of the lever and consequently the degreev of opening of the valve 83 so that the valve not only serves as an operating valve, but also to control or regulate the volume of compressed air to be admitted to the hammer whereby the operation and effective blows of the striker against the work and anvil may be' regulatqi to a nicety. As shown, the adjusting screw I00 is also provided with a reduced shank portion I05 which extends freely through an opening I06 in the lever 93 with an enlarged screw head I01 which freely moves through an enlarged opening I08 in the outer portion of the lever 93 so that the reduced opening I06 forms an outwardly facing shoulder to engage the inner face of the head to limit the outward displacement or throw of the lever while permitting inward swing thereof as far as the knurled head I02 and at the same time to press inwardly on the valve stem for the purpose of unseating the valve 83 to admit air to the chamber 8|. This chamber communicates through an inlet port I09 extending from the transverse and horizontally positioned bores or chambers leading into the cylinder chamber 5| at an intersecting angle substantially normal thereto or at a slight angle but horizontal and slightly below or tangentially relative to the chamber 8|. The inlet port or passage I09 is preferably bored from the back of the casting and is closed by a suitably threaded plug or the like, I ID.

- head 26 from damaged parts.

turned upwardly to space the bottom of the sleeve 40 from the top of the frame and particularly the fiat top portion of the sleeve extension 33, but more particularly, the skirt 25 or the hammer the die 20. After this, the hammer as raised in spaced relation to the die, may be readily applied to the work or metal to be straightened using the particular form of die and frame desired. The hose being connected to the source of fluid pressure or compressed air, the nut 38 is then turned on the post 34 to exert the proper pressure against the top of the sleeve 40 and the hammer head to force the latter downwardly against the work and by reason of the resiliency of the frame to adjust the device at the proper tension. During this adjustment, the head will slide downwardly on the post by turning down the nut 38 and shorten the gap or space between the bottom of .the sleeve 40 and the top of the sleeve extension 33, it being understood that the hammer head with the striker therein is engaged with the work between the hammer head and the die. The operator then grasps the hammer head at the cylinder 26 with either hand. If the right hand is used, the fingers will extend over the control lever 93 for effectively operating the latter. If the left hand is used, the thumb will extend over said lever. The throw of the lever for the control of the supply of air admitted to the cylinder upon unseating the valve 83 may be finely adjusted by turning the thumb wheel, disk or knurled head I02 and the grooves therein will indicate the desired amount of movement while the spring 91 at its projection 99 will engage the radial grooves and hold the adjacent screw against turning when set at any desired position. The head I 01 will prevent the lever from being outwardly displaced beyond a certain point. By opening the valve upon depression of the lever 93, air will be admitted to the cylinder to actuate end thereof and also above the striker or impact member thereof. It is not necessary to tightly grip the device in order to as this pressure is applied by turning down the nut 38 and as means for ten-. sioning the device and the frame, as well as the engagement of the hammer with the die and the pressure against the work, it is effectively held at any desired adjusted position and locked against retrograde movement of the spring catch or detent 41 engaging the depressions 46. By using the hammer head as a handle, the device can be readily guided from the top of the hammer with one hand while the other hand is grasping the frame I!) and may be more accurately controlled without particular tiring effect upon the operator. Also, the tension may be adjusted While the device is in operation merely by tuming the nut 38 and this pressure is maintained against the work so that the apron 25 of the hammer head and the die 20 will constantly hug the work and prevent chattering or movement of the hammer out of position. Release of the work is readily accomplished by unscrewing the nut 38 and it is to be understood that in the preferred use of the device, the tension is gradually increased as the straightening operation progresses so as to more quickly and efflciently iron out the The amount or volume of compressed air admitted depends upon the character of the work and the force of impact of the striker which is desired, and this may be efiectively controlled by the adjustment of the valve through the medium of the knurled head I02 which may be regulated from t me to time by manipulation down stroke,

thereof, after which the operation is controlled by the operating valve through the medium of the fingerpiece or lever 98 which is depressed to shift the valve for the purpose of opening the same while release of the lever will permit the valve to automatically close under the action of the air and the spring 11. Air is supplied through the conduit or pressure hose 10 to the receiving chamber 13 and when the valve 83 is opened by depression of the lever 93 and stem 80, the air is admitted through the port 18 and the discharge chamber From thence, the air passes through the inlet I09, to the cylinder at the chamber 69 to cushion the down or power stroke, assuming that the parts are in the position shown in Fig. 4 of the drawings. This forces the enlarged upper portion 62 of the piston and the striker upwardly in the bores or chambers 5| and 52 of the cylinder, thus raising the piston and striker since the air will be prevented from entering the inlet ports 64, but cushioning the upward o return stroke by the compression of the air in the top of the bore 5|. However, when the ports 64 are aligned with the chamber 69 and the inlet port I09, the air will pass into the central bore or chamber 63 to act on the lower the enlarged portion 62 of the piston to force the same downwardly to the position shown inFig. 4 to exhaust through the ports 65, the chamber 54 and the opening or slot 55 at the same time closing the ports Bl against the wall of the reduced bore 52. When the piston is raised, the exhaust ports 65 will be closed by the wall of the bore 52 until, on the the exhaust ports have reached the chamber 54 and the slot 55 when the compressed air will be discharged through the ports 65 and the down stroke of the piston cushioned by the compression of the air in the chamber 69. This operation is repeated at each reciprocation of the piston and striker or impact member. The kind of work dictates the selection of a frame member for cooperation with the hammer head, it being understood that the die in the die holder I2 is always perfectly aligned with the striker and the hammer head, as by being received within the skirt 25 thereof. The device, by reason of the construction described and the vertical sliding movement of th hammer head on the frame, may be readily and quickly applied to or removed from the work, while the adjustment of the nut 38 will serve to force the hammer head downwardly against the resiliency of the frame to place the latter under tension against the work between the striker or hammer head and the desired tension against played, and are effectively supported by the die holder I! of simple construction, as described.

When the lever 93 is released against the action of the spring 91, the lever will be forced outwardly to permit the valve 83 to automatically close so that the supply of air will be cut and the operation of the hammer immediately stopped. However, it is not necessary to exert extreme pressure in applying force or tension to the work, and slight pressure against the lever 93' will operate the valve 83, in connection with the use of the hammer head as a handle,'will have minimum tiring effect or tendency to cramp the set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A device of the kind described including a frame having confronting portions, an upright post on one portion, a hammer head freely slidable on the post, a die on the frame opposing the hammer head, a nut on the post engaging the head to press the same toward the die and means coacting between the nut'and the head to hold the nut against turning.

2. A device of the kind described including a resilient frame having supporting portions, a die on one supporting portion, a post on the other supporting portion, a hammer head having a sleeve extension freely slidable on the post, a nut on the post engaging the sleeve extension at the top and means to hold the nut against turning.

3. A device of the kind described including a resilient frame, an angular die holder on one portion of the frame, an upright post on the other portion of the frame, a hammer head having a rigid sleeve slidable on the post and held against turning horizontally thereon, a nut on the post engaging the sleeve, means on the nut engaging the sleeve to hold the nut from turning. said nut serving to place the frame under tension and gry the pressure between the head and the 4. A device of the kind described including a 5. A hammer of the class described including a holding frame, ahammer head on' the frame having a cylinder and an apron portion forming a handle, a compressed air line connected with a cylinder, a valve controlling the supply of air to the cylinder and a vertical lever adjacent the cylinder adapted to be operated for controlling the valve upon gripping the cylinder as 'a handle.

6. A hammer of the class described including .a holding frame, a hammer head on the frame having a cylinder and an apron portion forming a handle, a compressed air line connected with a cylinder, a valve controlling the supply of air to the cylinder, and means for adjusting the throw of said lever and the unseating of the valve.

'7. A hammer of the class described including a frame, a die on the frame, a hammer head having an extension with a sleeve freely slidable on the post, said post and sleeve having coacting flattened portions to prevent turning of the hammer head and sleeve on the post, means on the post to exert pressure against the sleeve to force the hammer head against the die, means to hold the last named means in adjusted position, a supply line communicating with a passage leading to the hammer head and a lever at one side of the head for unseating the valve. 3

8. A pneumatic hammer of the character described comprising a frame; a head and a die carried by said frame and adapted to engage work on opposite faces; means for tensioning said head relative to said die and the work therebetween;

manually'operable means for adjusting said ten-,

sioning means while the hammer is in operation; a source of supply of fluid under pressure connected to said head, and a control valve associated with said source of supply to control the delivery of fluid under pressure to said head; said control valve being arranged so that it may be operated by the flngers of a hand grasping said head for guiding purposes.

' 9. A device of the kind described including a holding frame, a motor body and a die on the frame, said body and die being adapted to receive work therebetween, means for adjusting the tension of said body and die on said work, said means including means for mounting the motor body for free vertical sliding movement, rotatable means for exerting pressure directly on the motor body and means for locking said rotatable means against turning.

10. A device of the kind described including a resilient frame, a motor body and a die on the frame in confronting relation and adapted to receive work therebetween, and means for adjusting the tension of the frame and of the motor body against the die and interposed work, said means including means for mounting the motor body for sliding movement on the frame toward and away from the die, means for exerting pressure directly on the motor body and means coacting between the last named means and the motor body to hold said last named means in" adjusted position.

FERDINAND H. BORM. 

